1. Field of the Invention
This invention relates to a cowling for an outboard motor, and more particularly to an air intake construction of the cowling.
2. Description of Related Art
A typical outboard motor employs an internal combustion engine for powering a propulsion device such as a propeller. A protective cowling normally encloses the engine therein to present a neat appearance but also to protect the engine. The cowling protects the engine from being wetted by the water in which the outboard motor is operated. Water, especially salt water, tends to damage engine components.
The protective cowling defines a generally closed cavity in which the engine is contained. The engine, however, must be supplied with copious amounts of air through an air induction device for combustion in its combustion chambers. For this purpose, the air induction system of the engine has an air inlet opening that is open to the cavity within the cowling. Conventionally, the protective cowling includes a rearwardly positioned, generally upwardly facing air intake duct that permits air flow into the cavity. The intake duct usually extends in an additional small cavity, which defines an air compartment. Air flow through the duct often is normal to the direction of air flow into the air compartment to cause water to drop out of the air flow before the air moves through the duct. This arrangement thus inhibits water from entering the main cavity of the cowling; however, it does not entirely prevent water from entering the cavity through the duct.
The air inlet opening of the engine induction system is normally positioned at a front portion of the cavity. Thus, the air must travel across the engine body from the air duct to the air inlet opening. This air flow advantageously cools various engine components, but it is also warmed through this process, which reduces charging efficiency. This problem is exacerbated with outboard motors employing four-stroke engines at these engines tend to run hotter than two-stroke engines.